The Role of Chance in the Evolution of Early Life
When: May 18, 2015 1PM PDT
The origin of life is believed to have progressed through an RNA World, in which RNA acted as both genetic material and functional molecules. Understanding early evolution requires systematic knowledge of the relationship between RNA sequence and fitness, as well as environmental effects. In particular, knowing the structure of the fitness landscape of RNA is critical to estimating the probability of the emergence of functional sequences and the role of historical accident during evolution. Much theoretical work has been devoted to fitness landscapes, but experimental maps have been relatively limited. The Chen lab uses in vitro selection on a pool of short RNA sequences that nearly saturates sequence space to reconstruct the form of a comprehensive fitness landscape. They also consider how spatial structure affects the degree to which chance determines evolutionary outcomes.